The main objective of this project is to measure cardiac function in normal human fetuses at different times in gestation, and to compare these findings with measurements obtained in compromised fetuses. The bulk of this year's effort has been in obtaining echocardiographic tracings from which can be measured: 1) systolic time intervals (STI), such as left ventricular ejection time (LVET), 2) indices of cardiac contractility such as mean velocity of circumferential fiber-shortening time (VCF) and posterior-wall velocity (PWV), and 3) echocardiographic indices such as ejection fraction (EF), stroke volume (SV), and left ventricular output (LVO). During this year we have evaluated 55 patients in whom we have been able to measure LVET in 25 cases and echocardiographic indices in 32 patients. LVET is measured from aortic valvular opening to aortic closure. The echocardiographic indices (CO, SV, and EF) are obtained from a tracing on which is superimposed right and left ventricle with an intervening interventricular septum. Thus far, we have found the LVT of the fetal heart in late gestation to be apporoximately 192.1 plus or minus 11.23 millisec. There is a strong positive correlation between LVET and heart rate. Also, SV and LVO have correlated positively with fetal weight. Surprisingly, the other indices correlated better with gestational age than weight. Our problems over the past year have included an inability in some cases to obtain images of sufficient resolution for meaningful data. We also have been unable to obtain ECGs (from the maternal abdominal wall) of sufficient quality to measure preejection period, an interval we had hoped to measure at the onset of the study. By utilizing an Echoline Scanner by Smith, Kline and French, however, we have now been obtaining echocardiograms of significantly better quality.